Electric shears



April 1956 P.- PADVA ELECTRIC SHEARS 2 Sheets-Sheet 1 Filed Nov. 19, 1954 if my INVENTOR, 4676/ may? arraA/ffls' April 1956 P. PADVA ELECTRIC SHEAR-S United States Patent Ofilice ELECTRIC SHEARS Philip Padva, Los Angeles, tric Tools, Inc., Venice, fornia Calif., assignor to Ungar Elec- Califl, a corporation of Cati- Application November 19, 1954, Serial No. 470,045 Claims. (Cl. 30-228) manufacture, safer from an electrical standpoint and more compact, and particularly more effective and eflicient in cutting cardboard or paper.

It is a feature of this invention that is provided, extensions of which are received respectively between the laminations of the core of the electromagnet and the laminations of the armature, thus reducing the overall dimensions of the shears.

It is a further object of this invention to provide the blades of this invention with a self-sharpening action which also assures a point contact of the blades at the vertex between them.

It is another object of this invention to reduce the noise resulting from the shock of the meeting of the two poles, and this is accomplished by means of a shock absorbing spring which ing in the opening of the a greatly reduced amplitude in the swing of the jaws.

These and other objects, features and advantages will be apparent from the annexed specification in which:

Figure l is a side view of a device embodying the present invention.

Figure 2 is an end view thereof taken along the line 2-2 of Figure 1.

Figure 3 is a view similar the casing removed, and of illustration.

a pair of blades jaws and also by reason of to Figure l with one-half of with parts cut away for clarity Figure 4 is a section taken along the line 44 of Figure 1.

Figure 5 is a section taken along the line 55 of Figure 3.

Figure 6 is a section taken along the line 6-6 of Figure 3.

Figure 7 is a section taken along the line 7-7 of Figure 3.

Figure 8 is a section taken along the line 8-8 of Figure 3.

of the switch mechperspective view of one of the insulatsection taken along the line has the dual function of assist- 2,740,197 Patented Apr. 3, 1956 Figure is a side view of a lower blade.

Referring now more particularly to the drawings, the shears are indicated generally by the numeral and include a plastic case held together by a pair of rivets 23 and 24. The rivet 23 is received in hollow bosses 25 and 26 extending inwardly towards each other in each of the halves 21 and 22, while the rivet 24 is received in hollow bosses 27 and 28 extending inwardly towards each other as shown.

The casing houses a laminated core 29 nated armature 30. Upon the core 29 there is wound a coil 31. A blade 32 is provided having an extension 33 disposed between the laminations of the core 29. Towards the rear end, the blade 32 is offset as at 34 and provided with a downwardly and forwardly bent portion terminating in a rounded arm 35. Intermediate the offset 34 and arm 35 this portion is enlarged as at 36 and provided with a circular opening 37. Holes 38, 39, 40 and 41 are formed in the blade 32 as shown. The lower edge of the blade 32 is notched as at 42 and 43 to leave a boss 44.

A second blade 45 is provided having an extension 46 disposed between the laminations of the armature 30. The rear end of blade 45 terminates in a rounded extension 47 and is provided with an upwardly extending portion 48 recessed as at 49 to form a hook. Holes 50, 51 and 52 are formed in the blade 45 and an elongated hole 53 is formed adjacent the front end of the blade. The upper edge of blade 45 is notched as at 54 and 55 to form a boss 56.

When the device is assembled, the blade 32 is arranged with hole 40 surrounding the reduced portion formed on the ends of bosses 25 and 26 and with the hole 37 surrounding the reduced portions formed on the ends of bosses 2'7 and 28, and the blade 32 is thus rigidly held by the rivets 23 and 24. The blade 45, however, is positioned to pivot at point 60, magnetic attraction holding laminated armatures 29 and 30 together to create the pivot point. Rivets 63 and 64 secure blade 45 in the laminations of the armature 30 and also serve to hold the laminations in place while rivets 65 and 66 similarly secure blade 32 in the laminations of the core 29.

A rivet 67 having a shank of lesser diameter than the elongated hole 53 passes through holes 41 and 53 and secures the ends of blades 32 and 45 together with a sliding fit. Flexibility at this point is afforded by the curved washer 68. a

In practice the blades 32 and 45 have a thickness of .050 inch; however, the offset 34 is made to extend .070 inch away from blade 45 thus spacing the rear ends of the two blades .020 inch apart. As the blades meet at the vertex 70, it will be apparent that they converge at a very small angle which is sutficient, however, to assure a point contact at the vertex and to render the cutting portions of the blades self-sharpening.

A spring 71 is inserted between blades 32 and 45, mounted on bosses 44 and 56 and serves a dual purpose of absorbing the shock of the pole faces meeting, thus reducing noise and aiding the material being cut to force the blades apart.

A fitting in the rear end of the casing serves to introduce a conduit 81 comprising a pair of wires 82 and 83. An insulating spacer 84 rests on the top of core 29 at its rear end, and wire 112 runs from coil 31 and a lami- Wire 82 attaches to connection 102 of contact strip 100 while wire 83 attaches to connection 88 of strip 104.

An insulating plate 90 is provided having at its forward end a depending portion 91 ending in rounded formed of two halves 21 and 22, I

portions 93. The plate has an elongated central slot 94 and a depending lug 95 having a shoulder 96. Depending lug 95 has its underside grooved as a guide for wire 112 and also to hold it in proper position. The rear end of plate 90 terminates in a substantially circular portion 97, and anupwardly extending lug 98 is formed on the plate 90 adjacent its front end. The plate 90 is provided with a groove 99 in which is mounted a contact strip 100 by means of a rivet 101. The strip 100 ends in connections 89 and 102. A groove 103 is formed in the top of plate 90 and strip 104 is mounted therein by rivet 105. Strip 104 ends in connection 88 and leaf spring 106.

A strip 107 is mounted on the under side of plate 90 forward of the slot 94 by means of rivet 108 and terminates in connection 109 and contact 110. A wire 111 extends from connection 109 to the coil 31 and a wire 112 extends from the other end of the coil to connection 89.

A switch button having a depending portion 121 ending in trunnions 122 extends through an opening at the top of the casing, and trunnions 122 are pivotally mounted in sockets 123 extending inwardly from the casing halves 21 and 22. The switch button 120 in cludes a nob 124 engaging the top of leaf spring 106.

The plate 90 is assembled with rounded portions 93 riding on shelves extending inwardly from the casing halves 21 and 22, extends longitudinally over the core 29 with the shoulder 96 of lug 95 engaging the shoulder 131 of spacer 84. This assembly may conveniently be retained by a paper wrapping 132 wound around the coil and over plate 90.

The operation of the above described device is as follows: With the conduit 81 attached to the conventional A. 0. outlet, the switch button is depressed by the thumb of the user thus forcing leaf spring 106 into contact with contact 110, thus energizing the coil. Spring 71, however, is of insufficient strength to remove the pole faces of core 29 and armature 30 from contact and the device remains inoperative. When the vertex 70 of blades 32 and 45 is pressed against material to be out, such as paper, cardboard or the like, additional force is applied tending to separate the blades and hence the core and armature. The successive reversals of current in the coil will thereafter cause the armature to approach the core and hence the blade 45 pivots about point 60. The amplitude of movement of the blade 45 is, however, small and as the distance between the blades at their cutting end is at all times smaller than a childs finger, I safe from harm. Even where the distance between the blades is great enough to permit entrance of a finger, no damage would occur due to the extremely small amplitude of movement. As the blades are pushed against the paper to be cut, blade 45 thus'reciprocates cutting the paper. The natural period of the spring 71 is less than 60 cycles per second and hence there is always present additional shock absorbing force in the spring tending to reduce noise.

While there has been described what is at present considered a preferred embodiment of the present invention, it will be appreciated by those skilled in the art that various changes and modifications can be made therein without departing from the essence of the invention and it is intended to cover herein all such changes the user, even though he be a small child is and modifications as come within the true spirit and scope of the appended claims.

I claim:

1. An electrically operated scissors comprising: a casing; a laminated core and a laminated armature mounted in said casing; a coil wound on said core; a fixed blade having a portion extending between the laminations of said core; a movable blade having a portion extending between the laminations of said armature; said blades extending out of said casing at one end and engaging each other to form a scissors.

2. An electrically operated scissors comprising: a casing; a laminated core and a laminated armature mounted in said casing; a coil wound on said core; a fixed blade having a portion extending between the laminations of said core; a movable blade having a portion extending between the laminations of said armature; a spring interposed between said blades and biasing said blades apart; and said blades extending out of said casing at one end and engaging each other to form a scissors.

3. An electrically operated scissors comprising: a casing; a laminated core and a laminated armature mounted in said casing; a coil wound on said core; a fixed blade having a portion extending between the laminations of said core; a movable blade having a portion extending between the laminations of said armature; a spring interposed between said blades and biasing said blades apart; said blades extending out of said casing at one end and engaging each other to form a scissors; and means adjacent the engagement of said blades to retain the same in close sliding contact.

4. An electrically operated scissors comprising: a casing; a laminated core and a laminated armature mounted in said casing; a coil wound on said core; a fixed blade having a portion extending between the laminations of said core; a movable blade having a portion extending between the laminations of said armature; a spring interposed between said blades and tending to bias said blades apart; the force of said spring being insuflicient alone to separate the poles of said core and armature; and said blades extending out of said casing at one end and engaging each other to form a scissors.

5. An electrically operated scissors comprising: a casing; a laminated core. and a laminated armature mounted in said casing; a coil wound on said core; a fixed blade having a portion extending between the lami' nations of said core; a movable blade having a portion extending between the laminations of said armature; a spring interposed between said blades and tending to bias said blades apart, the force of said spring being insufficient alone to separate the poles of said core and armature; said blades extending out of said casing at one end and engaging each other to form a scissors; means adjacent the engagement of said blades to retain the same in close sliding contact; and one of said blades being slightly offset from the other and approaching the other at a small included angle whereby said blades meet at a point contact.

References Cited in the file of this patent UNITED STATES PATENTS 

